Siemens SINAMICS S120 Function Manual page 823

Sequence of data transfer to closed-loop control system
1. Actual position value G1_XIST1 is read into the telegram image at time T
start of each cycle and transferred to the controllers in the next cycle.
2. Closed-loop control of the controller starts at time T
cycle and uses the current actual values read previously from the devices.
3. In the next cycle, the controller transfers the calculated setpoints to the telegram image of
the devices. The speed setpoint command NSET_B is issued to the closed-loop control
system at time T
Note
With the isochronous telegram setting, the complete SINAMICS device is in clock cycle
synchronism with all data. Reasons:
• Between the controller and device, all data are only exchanged in one IRT frame.
• In SINAMICS, all data are consistently processed in synchronism.
Designations and descriptions for motion control
Table 11- 15 Time settings and meanings
Name Limit value
T -
DC_BASE
T T_DC_MIN ≤ T_DC ≤
DC
T_DC_MAX
T CACF = 1-14
CACF
T T
CA_Valid CA_Valid
T T
CA_Start CA_Start
T
IO_BASE
Drive functions
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
after the beginning of the cycle.
IO_Output
Description
Time basis for cycle time T
calculation:
T
DC_BASE
Cycle time
T = T_DC · T
DC
CBE20:
T
DC_MIN
T
DC_MAX
X150 (CU3x0-2 PN):
T
DC_MIN
T
DC_MAX
IO controller application cycle time
This is the time frame in which the IO controller application generates new
setpoints (e.g. in the position controller cycle).
Calculation example:
T
CACF
< T Time, measured from the beginning of the cycle, at which the actual val-
DC
ues of all IO devices for the controller application process (position con-
trol) are available.
> T Time, measured from the beginning of the cycle, at which the controller
CA_Valid
application process (position control) starts.
Timebase for T
T
IO_BASE
11.3 Communication via PROFINET IO
DC
= T_DC_BASE · 31.25 µs = 4 · 31.25 µs = 125 µs
,T_DC: integer factor
DC_BASE
= T_DC_MIN · T = 4 · 125 µs = 500 µs
DC_BASE
= T_DC_MAX · T
DC_BASE
= T_DC_MIN · T = 2 · 125 µs = 250 µs
DC_BASE
= T_DC_MAX · T
DC_BASE
= CACF · T_DC = 2 · 500 µs = 1 ms
, T
IO_Input IO_Output
= T_IO_BASE · 1 ns = 125000 · 1 ns = 125 µs
IO_Input
after each position controller
CA_Start
= 32 · 125 µs = 4 ms
= 32 · 125 µs = 4 ms
Communication
before the
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